According to a new analysis by NYU Rory Meyers College of Nursing, tooth loss can lead to cognitive impairment and dementia. With each tooth lost, the likelihood of cognitive decline increases.

The study was published in JAMDA. This risk was not present in older adults who have dentures. It suggests that dentures can be treated promptly to prevent cognitive decline.

According to the Centers for Disease Control and Prevention, one in every six persons aged 65 and up has lost all of their teeth. Previous research has found a link between tooth loss and decreased cognitive performance, with experts providing a variety of probable causes.

For one thing, missing teeth can make chewing difficult, which might lead to nutritional deficits or brain abnormalities. A growing amount of evidence suggests a link between gum disease, a primary cause of tooth loss, and cognitive impairment. Furthermore, tooth loss may reflect long-term socioeconomic problems, which are risk factors for cognitive degeneration.

“Given the staggering number of people diagnosed with Alzheimer’s disease and dementia each year, and the opportunity to improve oral health across the lifespan, it’s important to gain a deeper understanding of the connection between poor oral health and cognitive decline,” said Bei Wu – the study’s senior author.

Wu and her colleagues used longitudinal studies of tooth loss and cognitive impairment to conduct a meta-analysis. The 14 research included in their review included 34,074 adults and 4,689 cases of patients with impaired cognitive function.

Even after controlling for other characteristics, the researchers discovered that adults with more tooth loss had a 1.48 times higher chance of having cognitive impairment and a 1.28 times higher risk of being diagnosed with dementia.

Adults without teeth were more susceptible to have cognitive impairment if they did not have dentures (23.8 percent) compared to those who did have dentures (16.9 percent); however, when individuals had dentures, the connection between tooth loss and cognitive impairment was not significant.

The researchers then looked at a sample of eight studies to see if there was a “dose-response” relationship between tooth loss and cognitive impairment—that is, if having more missing teeth was associated with a higher risk of cognitive decline. Their findings corroborated this link: each additional missing tooth was related with a 1.4 percent increased risk of cognitive impairment and a 1.1 percent increased risk of dementia diagnosis.

“This ‘dose-response’ relationship between the number of missing teeth and risk of diminished cognitive function substantially strengthens the evidence linking tooth loss to cognitive impairment, and provides some evidence that tooth loss may actually predict cognitive decline,” said Xiang Qi, a doctoral candidate from NYU Meyers.

“Our findings underscore the importance of maintaining good oral health and its role in helping to preserve cognitive function,” said Wu.

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